Currently it is not possible to trigger an action based on the mergable state of the PR; this creates a limitation on some possible workflows.
An example workflow would be auto updating PR when out of sync with the base branch. See this issue (
https://github.com/pascalgn/automerge-action/issues/16#issuecomment-546625489) for more context on functionality desired.
Unfortunately there is no current way to easily implement the above solution via GitHub actions.
